Judge: The case before me involves a plaintiff and three codefendants.
Conclusion
We cannot grant the request that the plaintiff be able to question each defendant one at a time (their counsel is allowed, but the other defendants and the other defendants' lawyers would have to leave the room).
Evidence
Two of the codefendants share the same lawyers, and we're not going to make any of these defendants find a new lawyer.
Evaluate
If all the defendants had their own lawyers, then granting this request would just mean that each defendant would have their lawyer present for some solo questioning, while all the other defendants and lawyers left the room.
But since Eddie and Bob have the same lawyer, Teresa, we're in a conundrum: If we're questioning Eddie, does Teresa get to stay or go?
Because Teresa is Eddie's lawyer, she should be able to stay. But because Teresa is one of the other defendants' lawyers (Bob's), she should go.
How can we resolve this? One possible way would be to tell Eddie and Bob that they can't share a lawyer. But the judge says that we're not going to do that.
The only other possible way would be to tell Eddie that he can't have his lawyer present.
Goal
Since the only way to grant this request (given that we can't make anyone get a new lawyer) is to make those two codefendants have their questioning without their lawyer present, in order to solidify the judge's ruling that we can't grant the request, we have to establish that we can't tolerate the idea of having the codefendants questioned without their lawyer present.